1. Field of the Invention
The present invention relates to radio receiving systems, and more particularly, to a method for tuning a receiving system to a radio broadcast frequency in a portable terminal.
2. Description of the Related Art
In general, radio broadcasting is an audio broadcasting service provided in such a way that a plurality of radio stations broadcast radio broadcast signals through the air and a radio broadcast receiver receives a broadcast signal corresponding to a user's selecting frequency via an antenna and outputs an audio sound to a speaker. The radio broadcast receiver includes a tuner that tunes to one of the broadcasting frequencies according to a user's selection, so that only a radio broadcast signal corresponding to the selected broadcast frequency can be received and then output. That is, the tuner serves to allow the receiver to receive only one of the radiowaves (broadcast signals) from a plurality of radio stations, which corresponds to a user's selected frequency band.
The types of radio broadcasting are amplitude modulation (AM) broadcasting and frequency modulation (FM) broadcasting. FM broadcasting is advantageous in that it can serve as stereo broadcasting and provide higher sound fidelity. FM broadcasting is more popular due to its advantages. However, FM broadcasting is disadvantageous in that it has a limited broadcast range. In order to perform nationwide FM broadcasting, a central FM station broadcasts FM radiowaves to local FM stations, and then the local FM stations broadcast them to corresponding areas, so that the FM radio receivers can receive the FM radio signals and provide audio sounds to users.
With the development of wireless communication technology, portable terminals now provide a variety of services, such as short message service (SMS), multimedia messaging service (MMS), video call service, digital media broadcasting (DMB) service, wireless Internet service, etc. as well as a voice call service. In recent years, portable terminals have included a radio broadcast receiver to provide radio broadcasts to users. In that case, the portable terminals may store information regarding a variety of elements to retain a high quality audio sound according to local areas. An example of the stored information is a tuning element that can tune a radio broadcast frequency in a reference local area and allow the radio broadcast receiver to receive a radio broadcast signal corresponding thereto.
Although the tuning element allows the receiver to receive radio broadcast signals from a plurality of radio stations, its operation information is fixed to a particular area, as a reference area, and then stored in the portable terminal. For example, a portable terminal manufactured for use in Europe may fix the tuning element to Germany, for example, as a reference area to check the radio quality and store the information related to the tuning element, so that the receiver can optimally receive radio broadcast signals from German radio broadcasting stations. However if a user takes the portable terminal to another country, such as Italy, for example, and then intends to listen to the radio signals, it starts to receive radio broadcast signals broadcast from Italian radio broadcasting stations through the tuning element fixed to a German radio broadcasting area, and then outputs the received signals. However, since an environment for receiving radio broadcast signals in Italy differs from that in Germany, the radio broadcast receiver may not provide a high quality audio sound when the user listens to the radio in this second country (e.g. Italy).
Therefore, a radio receiving system is required to be adaptively changed to radio broadcasting environments depending on where the receiving system is located and to provide high quality radio broadcasts to users wherever users listen to the radio.